Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
public class Main {
	public static void main(String[] args) {
		FastScanner sc = new FastScanner();
		PrintWriter pw = new PrintWriter(System.out);
		while (sc.hasNext()) {
			int n=sc.nextInt();
			int m=sc.nextInt();
			int[][]maze=new int[n][m];
			for(int i=0;i<n;i++){
				for(int j=0;j<m;j++){
					maze[i][j]=sc.nextInt();
				}
			}
			boolean row=true;
			if(n>m)row=false;
			boolean flag=true;
			ArrayList<String>list=new ArrayList<String>();
			while(true){
				int max=0;
				int a=-1;
				int b=-1;
				boolean c=false;
				for(int i=0;i<n;i++){
					int num1=0;
					for(int j=0;j<m;j++){
						if(maze[i][j]>=1){
							num1++;
							c=true;
						}
					}
					if(num1==m){
						a=i;
						break;
					}
				}
				for(int i=0;i<m;i++){
					int num1=0;
					for(int j=0;j<n;j++){
						if(maze[j][i]>=1){
							num1++;
						}
					}
					if(num1==n){
						b=i;
						break;
					}
				}
				//pw.println(a+" "+b);
				if(a==-1&&b==-1){
					if(!c){
						break;
					}
					else{
						flag=false;
						break;
					}
				}
				if(row){
					if(a>=0){
						list.add("row "+(a+1));
						for(int i=0;i<m;i++){
							maze[a][i]--;
						}
					}else{
						list.add("col "+(b+1));
						for(int i=0;i<n;i++){
							maze[i][b]--;
						}
					}
				}else{
					if(b>=0){
						list.add("col "+(b+1));
						for(int i=0;i<n;i++){
							maze[i][b]--;
						}
					}else{
						list.add("row "+(a+1));
						for(int i=0;i<m;i++){
							maze[a][i]--;
						}
					}
				}
			}
			if(!flag)pw.println(-1);
			else{
				pw.println(list.size());
				for(int i=0;i<list.size();i++){
					pw.println(list.get(i));
				}
			}
			pw.flush();
		}
	}
}

class FastScanner {
	BufferedReader br;
	StringTokenizer st;

	public FastScanner() {
		try {
			br = new BufferedReader(new InputStreamReader(System.in));
			st = new StringTokenizer("");
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public boolean hasNext() {
		while (!st.hasMoreTokens()) {
			String line = nextLine();
			if (line == null) {
				return false;
			}
			st = new StringTokenizer(line);
		}
		return true;
	}

	public String next() {
		while(!st.hasMoreTokens()){
			st=new StringTokenizer(nextLine());
		}
		return st.nextToken();
	}

	public int nextInt() {
		return Integer.parseInt(next());
	}

	public long nextLong() {
		return Long.parseLong(next());
	}

	public double nextDouble() {
		return Double.parseDouble(next());
	}

	public String nextLine() {
		String line = "";
		try {
			line = br.readLine();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return line;
	}
}